Terminal unit having a universal multi-protocol modular jack automatically sets its protocol to match with protocol of a modular plug connecting to the jack

ABSTRACT

A terminal unit of the present invention and applicable to a wired services network distinguishes two or more different kinds of plugs possibly connected to its general-purpose modular jack, reads a particular protocol matching the plug out of its storage, and then sets the protocol as its own protocol. Therefore, a plurality of data terminals each having a particular protocol can share a single terminal unit. In addition, a protocol adequate for a desired data terminal can be automatically set. This enhances the convenient use of terminal equipments.

BACKGROUND OF THE INVENTION

The present invention relates to a terminal unit for a wired servicesnetwork and, more particularly, to a terminal unit to be shared by aplurality of data terminals each having a particular connection terminalstructure and a particular protocol.

Today, due to the advent of miniature and handy data terminals, there isan increasing demand for a wired services network allowing each dataterminal to be operated at various locations. However, in a conventionalwired services system, terminal units situated at various locations areeach provided only with a single modular jack matching a particularprotocol assigned to the terminal unit. Therefore, a data terminalcannot be connected to a terminal unit unless the former shares the sameprotocol as the latter. To promote the efficient use of data terminals,a plurality of terminal units each having a particular protocol and aparticular modular jack must be situated at each location. This resultsin an increase in installation cost.

Apart from the cost aspect, the user of a data terminal must connect itto desired one of the multiple terminal units while surely finding amodular jack matching the modular plug of the data terminal, resultingin troublesome operation. Moreover, a modular jack for a public two-wireor four-wire line may not be correctly electrically connected to thecorresponding plug although the connection may be mechanically correct.Should the user of the data terminal be not informed of an incorrectelectrical connection, various kinds of troubles would occur.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a terminalunit for a wired services network and allowing a data terminal to beconnected thereto without regard to its protocol, and automaticallysetting up a protocol matching the data terminal.

A terminal unit of the present invention has a general-purpose modularjack capable of accommodating any one of a plurality of kinds of modularplugs. An identifying section identifies the kind of the modular plugconnected to the modular jack. A storage device stores a plurality ofprotocols each corresponding to the respective modular plug. A protocolconverter reads, based on the output of the identifying section, theprotocol matching the kind of the modular plug connected to the modularjack, and then sets the protocol as a protocol of the terminal unit.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will become more apparent from the following detaileddescription taken with the accompanying drawings in which:

FIG. 1 is a block diagram schematically showing a wired services networkincluding conventional terminal units;

FIG. 2 is a block diagram schematically showing a terminal unitembodying the present invention;

FIG. 3A is a partially sectioned front view of a modular jack includedin the embodiment;

FIG. 3B is a plan view of the modular jack shown in FIG. 3A; and

FIG. 4 is a block diagram schematically showing a specific configurationof a protocol converter included in the embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENT

To better understand the present invention, a brief reference will bemade to a wired services network including conventional terminal unitseach having a particular connection terminal structure assigned to aparticular protocol, shown in FIG. 1. Assume that three differentprotocols PR1, PR2 and PR3 are available with a wired services networkNW. Then, as shown in FIG. 1, terminal units 1A, 1B and 1C connected tothe network NW are each exclusively provided with one of three differentmodular jacks 10A, 10B and 10C. The modular jacks 10A, 10B and 10C maybe respectively assigned to Ethernet, public two-wire line, and publicfour-wire line, respectively, by way of example. In this condition, onlyif the user of a data terminal 100A having a modular plug 101A connectsit to the modular jack of the matching terminal unit 10A, 10B or 10C,the user can receive a wired service based on the preselected protocol.

However, the problem with the above terminal units 1A-1C is that becauseeach of them is provided only with a modular jack matching a particularprotocol, the data terminal 100A cannot be used if it is different inprotocol from the terminal unit.

Referring to FIG. 2, a terminal unit embodying the present invention isshown. As shown, the terminal unit, generally 1, has a general-purposemodular jack 10 capable of receiving any one of modular plugs 111, 121and 131 of different data terminals 110, 120 and 131. In theillustrative embodiment, the modular plugs 111, 121 and 131 arerespectively assigned to Ethernet, public two-wire line, and publicfour-wire line, respectively. The terminal unit 1 includes a plugdiscriminator 11 for identifying any one of the three different modularplugs 111, 121 and 131 connected to the modular jack 10.

A RAM (Random Access Memory) 12 stores three kinds of protocols PR1, PR2and PR3 respectively corresponding to the data terminals 110, 120 and130. When one of the plugs 111, 121 and 131 is connected to the jack 10as identified by the plug discriminator 11, a protocol converter 13selects one of the protocols RP1, RP2 and PR3 in response to the outputof the discriminator 11. The protocol selected is input to a controller14 and used to process signals input and output via the jack 10. Aman/machine interface 15 and a CPU (Central Processing Unit) 16 forcontrolling the terminal unit 1 are also built in the unit 1.

As shown in FIGS. 3A and 3B, the modular jack 10 has a bore 21 forreceiving the modular plugs 111, 121 and 131. The width of the bore 21is great enough to accommodate the largest modular plug 111 assigned toEthernet. A pair of spaced leaf springs 22 are positioned at oppositesides of the bore 21. In an unstressed condition, the leaf springs 22protrude toward each other to form a space corresponding in size to themodular plugs 121 and 131 which are smaller than the modular plug 111. Aplurality of connection pins 23 are provided on the jack 10 to beconnected to the modular plug 111, 121 or 131. The number of the pins 23is the same as the largest number of terminals which the plug 111, 121or 131 has.

A microswitch 24 is positioned between one side wall of the jack 10 andone of the two leaf springs 22. When the leaf springs 22 are convextoward each other due to the absence of the Ethernet plug 111, themicroswitch 24 remains in its OFF state. When the Ethernet plug 111 isinserted into the jack 10 while causing the leaf springs 22 toresiliently deform outward, the leaf spring 22 adjoining the microswitch24 brings it to its ON state.

The plug discriminator 11 monitors the electrical connection states ofthe microswitch 24 and pins 23. When the microswitch 24 is turned on bythe adjoining leaf spring 22, it is possible to determines that theEthernet plug 111 has been inserted into the jack 10. When themicroswitch 24 is not turned on, it is possible determine that eitherone of the two- and four-wire plugs 121 and 131 has been inserted intothe jack 10 on the basis of the number pins 23 electrically connected tothe terminals of the plug 121 or 131. Specifically, when two pins 23 areelectrically connected to the plug, the plug is determined to be thetwo-wire plug 121. When four pins 23 are electrically connected to theplug, the plug is determined to be the four-wire plug 131.

As shown in FIG. 4 specifically, the protocol converter 13 has a ROM 31storing three different synchronizing patterns P1, P2 and P3representative of three different protocols. Exclusive OR (EXOR) gates321, 322 and 323 respectively compare the synchronizing pattern Px of aninput signal with the synchronizing patterns P1, P2 and P3 read out ofthe ROM 31. As a result, one of the patterns P1-P3 coincident with thepattern Px is selected. Specifically, the output of each of the EXORgates 321-323 goes low if the respective pattern P1, P2 or P3 iscoincident with the pattern Px or goes high if the former is notcoincident with the latter.

The outputs of the EXOR gates 321-323 are connected to counters 331-333,respectively. A conversion 34 is responsive to the output of any one ofthe counters 321-323 and representative of N consecutive low levels,taking account of an N-bit error. The resulting output of the conversion34 is input to the CPU 16. In response, the CPU 16 returns a convertsignal to the conversion 34. Consequently, the conversion 34 selects oneof the patterns P1-P3 corresponding to the above counter. Then, theconversion 34 reads one of the protocols PR1-PR3 corresponding to theabove pattern out of the RAM 12 and delivers it to the controller 14.The controller 14 therefore processes signals on the basis of thereceived protocol.

In operation, assume that the data terminal 120 with the two-wiremodular plug 121 is connected to the terminal unit 1 via the modularjack 10. Then, because the microswitch 24 remains in its OFF state andbecause two of the pins 23 are electrically connected to the plug 121,the plug discriminator 11 determines that plug 121 has been insertedinto the jack 10. The resulting output of the plug discriminator 11 issent to the CPU 16.

When a signal is input from the data terminal 120 to the terminal unit 1via the jack 10, the protocol converter 13 causes its EXORs 321-323 tocompare the synchronizing pattern Px of the input signal with thesynchronizing patterns P1-P3 stored in the ROM 31. In this specificcase, the synchronizing pattern Px and P2 compare equal. The counter 332therefore counts N consecutive coincidences. On receiving the output ofthe counter 332 representative of N coincidences, the CPU 16 determinesthat the pattern Px of the protocol is coincident with the pattern P2.The CPU 16 makes a final decision with the output of the plugdiscriminator 11 and that of the protocol converter 13, and returns asignal representative of the result of the final decision to theprotocol converter 13. In response, the protocol converter 13 reads theprotocol PR2 stored in the RAM 12 and sends it to the controller 14. Thecontroller 14 processes signals on the basis of the protocol PR2. In thesame manner, when the four-wire plug 131 or the Ethernet plug 111 isinserted into the jack 10, the terminal unit 1 identifies it and selectsthe corresponding protocol.

In the embodiment described above, only if the user of any one of thedata terminals 110-130 inserts its plug 111, 121 or 131 into the jack 10of the terminal unit 1, the unit 1 automatically sets up the protocolmatching the data terminal and processes signals with the protocol.Therefore, a single terminal unit 1 situated at each location of a wiredservices network can be shared by all the data terminals without regardto the kind of protocol. This enhances the convenient use of dataterminals.

In the illustrative embodiment, an adequate protocol is selected on thebasis of the kind of the modular plug inserted into the modular jack 10and the synchronizing pattern of a signal actually input. This insuresadequate protocol setting at all times. If the protocols and modularplugs surely have one-to-one correspondence, then one of the protocolsmay be set up only by determining the kind of the modular plug in orderto simplify the terminal unit 1. In such a case, the RAM 12 will bedirectly driven by the convert signal output from the CPU 16.

In summary, in accordance with the present invention, a terminal unitfor a wired services network distinguishes two or more different kindsof modular plugs possibly connected to its general-purpose modular jack,reads a particular protocol matching the plug out of its storage, andthen sets the protocol as its own protocol. Therefore, a plurality ofdata terminals each having a particular protocol can share a singleterminal unit. In addition, a protocol adequate for a desired dataterminal can be automatically set. This enhances the convenient use ofterminal equipment.

Various modifications will become possible for those skilled in the artafter receiving the teachings of the present disclosure withoutdeparting from the scope thereof.

What is claimed is:
 1. A terminal unit comprising:a general-purposemodular jack capable of accommodating any one of a plurality of kinds ofmodular plugs; identifying means for identifying the kind of the modularplug connected to said modular jack; storing means for storing aplurality of protocols each corresponding to a respective kind ofmodular plug; and protocol converting means for reading, based on anoutput of said identifying means, a matching protocol that matches thekind of the modular plug connected to said modular jack, and thensetting said matching protocol as a protocol of said terminal unit.
 2. Aterminal unit as claimed in claim 1, wherein said identifying meansidentifies the kind of the modular plug on the basis of an ON/OFF stateof a switch mounted on said modular jacket and actuated on the basis ofa difference in size between the modular plugs, and a number of pinselectrically connected when the modular plug is connected to saidmodular jack.
 3. A terminal unit as claimed in claim 2, wherein saidswitch takes an ON state when the modular plug assigned to Ethernet isinserted into said modular jack or takes an OFF state when the modularplug assigned to a public line is inserted into said modular jack, andwherein a particular number of pins are connected when each of themodular plug assigned to a public two-wire line and the modular plugassigned to a public-four wire line is connected.
 4. A terminal unit asclaimed in claim 3, wherein said protocol converting means comprisesmeans for storing protocol synchronizing patterns each corresponding toa particular protocol, compares a protocol synchronizing pattern ofsignals input and output, and determines the matching protocol when anyone of stored protocol synchronizing patterns coincides with theprotocol pattern of signals input and output.
 5. A terminal unit asclaimed in claim 4, wherein said terminal unit is connected to a wiredservices network and sets, when the modular plug of any one of aplurality of data terminals each having a particular protocol isinserted into said modular jack, the protocol of the data terminal as aprotocol of said terminal unit.
 6. A terminal unit as claimed in claim3, wherein said terminal unit is connected to a wired services networkand sets, when the modular plug of any one of a plurality of dataterminals each having a particular protocol is inserted into saidmodular jack, the protocol of the data terminal as a protocol of saidterminal unit.
 7. A terminal unit as claimed in claim 2, wherein saidprotocol converting means comprises means for storing protocolsynchronizing patterns each corresponding to a particular protocol,compares a protocol synchronizing pattern of signals input and output,and determines the matching protocol when any one of stored protocolsynchronizing patterns coincides with the protocol pattern of signalsinput and output.
 8. A terminal unit as claimed in claim 7, wherein saidterminal unit is connected to a wired services network and sets, whenthe modular plug of any one of a plurality of data terminals each havinga particular protocol is inserted into said modular jack, the protocolof the data terminal as a protocol of said terminal unit.
 9. A terminalunit as claimed in claim 2, wherein said terminal unit is connected to awired services network and sets, when the modular plug of any one of aplurality of data terminals each having a particular protocol isinserted into said modular jack, the protocol of the data terminal as aprotocol of said terminal unit.
 10. A terminal unit as claimed in claim1, wherein said protocol converting means comprises means for storingprotocol synchronizing patterns each corresponding to a particularprotocol, compares a protocol synchronizing pattern of signals input andoutput, and determines the matching protocol when any one of storedprotocol synchronizing patterns coincides with the protocol pattern ofsignals input and output.
 11. A terminal unit as claimed in claim 10,wherein said terminal unit is connected to a wired services network andsets, when the modular plug of any one of a plurality of data terminalseach having a particular protocol is inserted into said modular jack,the protocol of the data terminal as a protocol of said terminal unit.12. A terminal unit as claimed in claim 1, wherein said terminal unit isconnected to a wired services network and sets, when the modular plug ofany one of a plurality of data terminals each having a particularprotocol is inserted into said modular jack, the protocol of the dataterminal as a protocol of said terminal unit.